Stands are the main power system from JoJo’s Bizarre Adventure, and they are a psychic manifestation of their ’s soul/psyche/fighting spirit/whatever, often having a unique ability of some sort.
King Crimson normally belongs to a major villain named Diavolo, who is a power-hungry man that wants to rule Italy uncontested, but doesn’t want anyone to know who he is or what he looks like. Also, his name is literally the Italian word for “devil”.
Not sure if missed meme, or playing along.
The figure beside Fluttershy is a Stand called King Crimson.